A direct fire 40mm round, with a 30-gram rubber projectile filled with & OC This round was designed for a single target engagement allowing escalation of force from a safe distance prior to use of lethal means. The & OC IMPACT Round was developed to overcome the shortcomings of conventional direct fire rubber ammunition. PT 750-OC Based on our PT-750 Impact round, this round is loaded with  O.C powder  and erupts on impact.